Record tablet



June 9, 1936. L. D. NORTON RECORD TABLET Filed Feb. 12, 1952 INVENTORM4/.9. Wm

' BY zwwby @Zw l M ATTORNEYS Patented June `9, 1936 UNITED STAT EsPATENT omer 2,043,769] `j I ARECORD TABLET Leland n. Norton,Briagepoaconn., assignorfto Dictaphone Corporation, New York, `N. Y.,` acorporation `of New York 1 j I Application February 12, lssaseriamo.592,548

.- This invention relates" to sound record tablets and with regard tocertain more specific features to reinforced sound recordtablets.

`One of the objects of the invention `is to provide 1'5"? aninexpensive,reinforcingmediumfor a sound4 record` tablet, said. mediumbeing `substantially and arrangements ofiparts which willbeexemplifiedin the structure to be hereinafter described and the scope oftheapplication of which willbe indicated in the following claims.

In lthe accompanying drawing, in which` is shown one of the variouspossible embodiments of the invention, i Figure 1 is averticalaxialsection of a cylindrical sound record ,tablet which embodies theinvention; Y I I f Figure 2 `is a vertical axial section of a mold usedin makingthesoundrecord tablet of Figure 1, and shows a reinforcementembodying the invention positioned on the c ore of the mold;

, `Figure 3 is `a fragmentary detail plan viewfof the, reinforcingmedium of Figure 2; and,

Figure 4 is a verticahsection `taken` on line 4-,-4ofFigure3.,Corresponding reference characters indicate correspondingpartsthroughout the several views of the drawing..` Referring now more..particularly to Figure 1, there is shownatnumeral I a sound recordtabletin the form of a hollowv cylinder, upon the outer surface 3 of `which a.soundrecord is adapted to be recordedsby a suitablerecording stylus, thesound record thusmade ,being-capable of later `rc'aproduction by asuitable reproducing stylus.

During` thewabove operations the soundrecord tablet `is usuallysupported upona mandrel havingresilient means, comprising.` frictiondevices, for rmlyengaging the inner surface of the sound record tablet,`and .holding it against" rotational movement or longitudinalmovementrelative to the mandrel. The mandrel upon whichthe record tabletis'placed is taperedfan'd consequently the, internal 5 "of the record isalso tapered.

Numeralsl and 9 indlcatethe `larger and ,top of the shell 23.

smaller `ends ofthe taper respectively, The taper is provided amongother reasons, to` enable the tablet to be easily withdrawn frornthecorewhen f being made and to allow the tablet to be easily applied to andremoved lfrom the mandrel. Inv 5 order to improve Vthe grip of themandrel `upon 4the tablet, the inside surface 5 is fluted withhellcalribs IIland grooves II.

The cylinderg Iiduring the recording and reproducing,operations,jandeven whennot` positioned 10 I `on. almandrel is subject to variousstresses and strains caused by temperature-changes and by the friction`devices on' the mandrel. Stresses and strains mayresult also fromdroppingthe record or from hitting. itagainst a. solidobject.` For 15these andlother, reasons ithas been customary to embody in the -.Waxlikematerialx I3 from which therecordtablets I I` aremade, a reinforcingme,- dium I5, which tends to prevent thestresses and strainsfromcracking the cylinder. VIt is `advan-` 20 tageous to have a. reinforcingmedium I5 towhich the wax-like material Iateffectively` adheresbecause,.ln the event of4 a blow which is great enoughtto shatter orcrack the record, notwithstanding the. reinforcing liningIS, thereinforc- 25 I ing `mediumshould be able to holdthe piecesof shatteredwaxlikematerialin close contact with each other inthe position whichthey' were prior to theshattering or cracking. Rubber reinforc-` inglinings I5 have been used for this purpose 30 and are.effective in`holding the pieces lof the shattered record together, becausethecongealed wax-like material tends to adhere to therrubbe'r lining.`However, in some instances .the rubber lining is not `entirelysatisfactory, because the 35 heat of the molten wax-like materialsoftens the lining, which is then "ableto moveinto the hollows of thehelix I2 of the core land` so is positioned inthe ribs I0 of the moldedrecord cylinder. The presence 'of rubber lining in the ribs I0 mayinter- 40 ferev later with the rearningofA the cylinder, by gumming upthe reamer. s

AA record cylinder such as isshown in Figure 1 may be produced inmanufacture from a mold I1, as shown in Figure 2; The ribs IllAandgrooves 45 II are produced bypa c ore I 9 having` a helical `surfacewhich core is mounted n a base 2l lof the mold I1, the base `alsoholding a shell` 23 concentrically of the core I9, In the `manufactureof the record, themolten wax-like material I3 is 50 poured into theshell through the openingfat the After the wai-ry material I3 cooled'offsuicientlyto congeal, `the shell-23 l is removed `from the record tabletby any suitable means, and the core I8 is removed-by screwing it 55outof vthe record. Thus in this way the ribs I and grooves II act as athread to facilitate the withdrawal of the core from the record.

Prior to the pouring of the wax-like material AI3 into the shell 23 thereinforcing medium I5 is positioned over the core I9. The reinforcingmedium essentially comprises a tapered tubular lining, and is made tojust ,touch the crests I 2 of the helix formed upon the core. It isdecidedly advantageous that the helix be preserved in the finishedcylinder, and hence it is desirable that the lining I be sufficientlyporous or openmeshed to allow the molten material I3 to iiow throughfrom the outside of the lining as it is poured into the shell 23 to thesurface of the core I9, whereby the lining I5 is substantially entirely'embedded within the waxy cylinder thus formed.

As above pointed out, it is desirable that the wax-like material I3 andthe reinforcing lining I5 adhere to each other; and it is furtherdesirable that the lining I5 be slightly elastic, or if it be inelastic,that the bond between the lin-- ing I5 and thewax-like material I3 beslightly elastic, in gorder that the differences in the expa'nsions ofthe wax-like material I3 and the lining I5 due to changes in temperaturemay beA compensated. It has been customary to use a relativelynon-elastic material such as crinoline as a reinforcing medium I5.Thecrinoline is not affected by the heat of the molten wax-'likematerial I3 and so does not move into the grooves of the core helix whenthe material' I3 is in a molten condition. However, the use of crinolinealone is vnot entirely satisfactory because the wax-like material doesnot adhere to the crinoline after congealing'and in the event ofshatteringof the record thev individualpieces of the wax-like materialmay fall away from the reinforcing medium I5. Further, the helicesformed on the ,interior of a. record cylinder, because of theintervening layer of reinforcing material, are not very securely unitedwith the waxy material yforming the body of the cylinder, so that unlessthere is effective adhesion between the waxand the lining, the threadsof the helix are apt to bebrok'en or chipped olf by contact with theends of the mandrels upon which the cylinder is'used, Q As a'result thecylinder is unevenly supported when seated upon a mandrel for use inrecording or reproducing. Thus the cylinder is subjected to unevenstresses and strains, and is likely to become cracked or the recordingor reproduction to be distorted. Furthermore, the crinoline,'beingsubstantially inelastic, may of itself cause cracking of the waxmaterial I3 when the cylinder is subjected to temperature changes,because ofthe different coefiicients of expansion of the wax-likematerial and the crinoline.

In the present invention I have provided an improved reinforcing liningI5 which overcomes all of the above-mentioned difficulties. My liningcomprises the usual open-meshed fabric 25, such as crinoline, or thelike; but I treat the fabric 25 with a binder 21 (see Figures 3 and 4)which accomplishes the desired results. I have found that a binder 21which adheres to the crinoline 25, and also to the wax-like material,and which of itself possesses `some Aelasticity is satisfactory. The'binder 21, which I propose to use also should be of such a nature thatit may be applied to the crinoline 25 without filling up the intersticesof the crinoline; otherwise, the molten wax-like material I3 could not.flow through the lining I5 to the surface of the core I9 as abovedescribed.

I have found that a material such as, for example, latex rubber(coagulated latex) fulfills the requirements of a satisfactory binder21; and that a crinoline lining 25, coated with latex rubber, sticks toor adheres to the congealed waxlike material I3 and vice versa. Further,the latex rubber' is sufficiently pliable and elastic to compensate forthe differences in the expansions of the two materials (the crinolineand the material I3) with temperature changes.

The manufacture of a cylindrical sound record employing my invention maybe carried out as follows:

A sheet of the open-meshed fabric 25 is rst treated with a solution oflatex rubber or the like, before it is formed into a tube. Care is takento use a thin solution, to prevent the latex rubber from filling in theinterstices of the openmeshed fabric. The solvent of the solution isthen evaporated, and the individual threads of the crinoline are leftcoated with a lm of latex rubber. The crinoline sheet is now cut to theproper sizes and permanently formed into tubes byv juxtaposing'edges ofthe sheets, and pressing them together. The edges are held in thisposition by the adhesive properties of the binding agent 21. In this waythe reinforcing tubes or linings I5 are formed without additionalfastening means such as thread, rivets, or the like.

A crinoline tube I5 with theindividual threads coated with rubber latexis now positioned on the core I9 and the molten waxy material I3 pouredinto the Shen 23. The wax nows through the interstices of the lining I5which have not been closed by the latex rubber 21. As hereinbeforepointed-out, the crinoline 25 is not affected by the heat of the moltenwax I3 and does not stretch into the hollows of the corehelix, butretains its shape throughout the pouring of the wax I3. The molten waxcoming into contact with the binding agent 21 on the individual threadsof the crinoline adheres to the agent 21 after congealing. In the eventof shattering of the record the shattered pieces of waxare held in closecontact with each other because of the lining I5 and the bindingmaterial 21.

Although I am not aware of the exact physical and/or chemical actionwhich takes place between the molten and/or congealed wax-like materialI3 and the latex rubber 21, I am aware that the congealed wax-likematerial does adhere firmly to the latex rubber. Other binding agentsmay be used to accomplish this binding between the crinoline 25'and thewax-like material I3, and accordingly I do not wish to limit myinvention to the use of latex rubber.

A record manufactured in accordance with my invention will not fall topieces when subjected to a shattering, butv will maintain its originalshape, the pieces of the wax-like material being held together firmly bythe crinoline, so that reproduction of the record is possible eventhough the cylinder be broken. Moreover, pieces of wax-like materialwhich are chipped from the interior of the cylinder by the ordinary wearand tear of putting a cylinder on and taking lt off a mandrel, areretained in position by the adhesive and elastic action of the binder21.

As various embodiments might be made of this invention, and as variouschanges might be made in the construction herein described, all Withoutdeparting from the scope of the invention,

it is to be understood that all matter herein set forth or shown in the`accompanying drawing is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. A sound record tablet having a sound recording surface and a mandrelcontacting surface, reinforcing means embedded in said sound recordtabletbetween said surfaces, said means comprising open-mashedrelatively non-elastic fabric, and unvulcanized elastic rubber coveringthe strands Without filling the meshes of said open-meshed fabric.

2. A sound record tablet having a sound recording surface and asupporting surface, reinforcing means embedded between said surfaces,said means comprising an open-meshed relatively inelastic fabric, andelastic means separating said fabric from the material ofsaid record,said means comprising a coating of latex rubber surrounding the fibreswithout filling the meshes of said fabric.

3. A sound record tablet having a sound recording surface and asupporting surface, a reinforcing means embedded between said surfaces,said means comprising an open-meshed, unvulcanized rubber treatedrelatively inelastic fibre fabric.

4. A sound record tablet having a sound recording surface, a supportingsurface, and a reinforcing means embedded between the said surfaces,said means comprising a perforate unvulcanized rubber treated relativelyinelastic material. i

LELAND D. NORTON.

